Pope Benedict XVI is making his first official visit to the Americas, with a trip to Brazil. BBC Rome correspondent David Willey is covering the visit and recording his thoughts in a daily diary.
DAY TWO: THURSDAY 10 MAY 2007
Aparecida and the bishops
Once in roughly every 10 years the Catholic Bishops of Latin America and the Caribbean gather for a jumbo meeting to decide on policy issues for the coming decade.
That is the main reason why Pope Benedict is here in Sao Paulo on his first trip to the Americas.
The pope is to address the CELAM gathering on Sunday
He is due to give the keynote speech at the opening on Sunday of the CELAM bishops' gathering in the bustling Catholic shrine town of Aparecida, situated in former gold mining country half-way between Brazil's two biggest cities, Sao Paolo and Rio de Janeiro.
Aparecida, which means apparition in Portuguese, takes its name from the finding of a small, broken clay statue of the Virgin Mary, fished out of a local stream at the beginning of the 18th Century.
The restored statue, dressed in a blue robe, crowned with jewels and enthroned in a silver and gold niche, has become the centrepiece of what is now one of the biggest and most visited Catholic shrines anywhere in the world.
Five million people travel from all over Brazil to pray here each year to the Virgin of Aparecida, who has been officially declared Brazil's patron saint.
When I was last here in 1980 with Pope John Paul, we travelled to Aparecida for the consecration of this huge and extraordinary temple of worship in the shape of a Greek cross with its four 40m-high naves and a 70m-high cupola.
The building can hold up to 45,000 people and in comparison seems to me to dwarf even Saint Peter's in Rome.
The sanctuary of Aparecida can hold up to 45,000 people
The first pope to travel across the Atlantic from Rome to open a meeting of Latin American bishops was Paul VI.
He attended their gathering at Medellin in Colombia in 1968 to try to stem a new tide of liberal Catholicism sweeping South America.
A tug-of-war has been going on between the Vatican and Catholic liberals ever since the CELAM was founded (in Rio De Janeiro) just over half a century ago.
Latin Americans were among the most progressive voices heard at the Second Vatican Council held in Rome in the early 1960s.
Paul VI came to challenge the authority of the Liberation Theologians, as they were called, because they gave priority to achieving immediate political and social progress for Catholics in this part of the world, rather than to preach to them about salvation in the next world.
The Vatican feared that the Latin American Catholic Church risked being dominated by a bunch of Marxists.
It was significant that the very first foreign trip of the globe-trotting Pope John Paul II was to Mexico City to open the CELAM meeting there in 1979.
Pope Benedict was later given the task by John Paul of bringing the Liberation Theologians to order.
In the 1980s, as head of the Vatican department in charge of keeping order among turbulent priests, he sacked the leading Brazilian exponent of the movement, Leonardo Boff, and only recently disciplined another leading member, the Spanish theologian, Jan Sobrino.